Titanium silicalite catalysts can be used in epoxidation reactions to form oxiranes. Oxiranes are compounds that are useful in a variety of end use applications. Epichlorohydrin (“epi”), for example, is an oxirane that can be used to make epoxy resins. The epoxidation reaction can include reacting an olefin with a peroxide compound in the presence of a catalyst and a solvent mixture with an alcohol and one or more non-reactive co-solvent(s). For example, allyl chloride can react with hydrogen peroxide to form epichlorohydrin.
Titanium silicalite catalysts can become fouled during the epoxidation reaction. For example, titanium silicalite catalysts have small pores that can become plugged over time by organic materials in the epoxidation reaction. Using a fouled titanium silicalite catalyst in the epoxidation reaction can reduce the amount of oxirane produced, thereby increasing the cost of production.